The Software

We developed an interactive modeling system for creating scenes to render in the colored-pencil style. The user has the option of modeling directly in colored pencils, in a more realistic view, or in any of about 6 intermediate modes. This may make visualizing the final output easier.

There are several different shape primitives available in this system: Spheres, Cones, Cubes, Disks, Cylinders, and Meshes. The mesh format supported is that used in meshes at Washington's "Grail" group. These primitives can be animated either by hand or using the special animation specification file format we've developed. After animating to their satisfaction, the user can write either an individual frame (into a TIFF file) or the entire animation (into an AVI file).

Usage

When you start the program it will ask for a scene file. Select one of the sample ones (or create your own - see below). This file will provide the shapes (and optionally, animation) for the project. When the program starts up, it is by default drawing in GL mode. To change this, use the Choice below the menu-bar. To manipulate the camera, use button 3 for rotation and 2 for zooming. To manipulate shapes, choose the type of manipulation from the drop-down menu - Translation, Rotation X, Rotation Y, or Rotation Z. Click button 1 on an object, and drag to manipulate.

The number of frames is set in the scene file. Select which frame by using the VCR widgets above the render window. There are single-step forward and backward buttons, a play button, a frame slider, a "double" slider to select a range of frames to loop over, a loop-toggling button, and a emnu for setting some less-used options.

Scene File Format

The scene file is ascii text, with each command occurring on one line. Comments are allowed and are delimited with the # sign. Here are the commands:

SPHERE name radius tX tY tZ [COLOR R G B]

This command creates a sphere of the given radius, centered at the position (tX,tY,tZ) with the optional color R/G/B. All shapes are required to be named for animation purposes.

CUBE name size tX tY tZ [rX rY rZ] [COLOR R G B]

This command creates a cube with an optional rotation.

DISK name inrad outrad tX tY tZ [rX rY rZ] [COLOR R G B]

Creates a flat disk with given inner and outer radii.

CYLINDER name radius height tX tY tZ [rX rY rZ] [COLOR R G B]

Creates a cylinder with given radius and height.

CONE name toprad bottomrad height tX tY tZ [ rX rY rZ ] [ COLOR R G B ]

Creates a cone with given top and bottom radii, height between them, etc.

MESH name filename tX tY tZ [ rX rY rZ ] [ SCALE sX sY sZ ] [ COLOR R G B ]

Reads the given file to determine a mesh (see GRAIL for mesh details). An optional scaling is possible.

TOTALFRAMES num

Gives the total # of frames for the animation

SETFRAME num

sets the "current" frame into which all animation data goes.

SHAPE name tX tY tZ [ rX rY rZ ]

moves the given shape to the given position, with an optional rotation.


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